import { expect, test } from '@playwright/test';
import { degrees, PDFDocument, StandardFonts, rgb } from 'pdf-lib';
import { TextOverlayError } from '../../src/lib/pdf-errors';
import {
	TEXT_OVERLAY_MARGIN,
	drawTextOverlay,
	getRotatedBoxPlacement
} from '../../src/lib/pdf-text-overlay';
import { getPageText, getPageTextAngle, getPageTextMatrix } from '../e2e/helpers';

const PAGE_WIDTH = 420;
const PAGE_HEIGHT = 594;
const MARGIN = 28;

/**
 * Maps a point from default user space to the displayed page. Viewers rotate the
 * content clockwise by `/Rotate`, so this is the forward transformation.
 */
const toVisualPoint = (
	point: { x: number; y: number },
	rotation: number,
	width: number,
	height: number
) => {
	switch (rotation) {
		case 90:
			return { x: point.y, y: width - point.x };
		case 180:
			return { x: width - point.x, y: height - point.y };
		case 270:
			return { x: height - point.y, y: point.x };
		default:
			return point;
	}
};

const createPageWithMark = async (rotation: number) => {
	const document = await PDFDocument.create();
	const font = await document.embedFont(StandardFonts.Helvetica);
	const page = document.addPage([PAGE_WIDTH, PAGE_HEIGHT]);
	page.setRotation(degrees(rotation));
	drawTextOverlay(page, {
		font,
		text: 'Bl. 1',
		size: 11,
		color: rgb(0.1, 0.1, 0.1),
		position: 'bottom-center',
		margin: MARGIN,
		compensatePageRotation: true
	});

	return PDFDocument.load(await document.save());
};

for (const rotation of [0, 90, 180, 270]) {
	test(`bottom-center mark stays at the visual bottom on a /Rotate ${rotation} page`, async () => {
		const output = await createPageWithMark(rotation);
		const matrix = getPageTextMatrix(output, 0);
		const visualWidth = rotation % 180 === 0 ? PAGE_WIDTH : PAGE_HEIGHT;
		const origin = toVisualPoint({ x: matrix.x, y: matrix.y }, rotation, PAGE_WIDTH, PAGE_HEIGHT);

		// Horizontally centred on the displayed page.
		expect(Math.abs(origin.x - visualWidth / 2)).toBeLessThan(30);
		// Close to the bottom margin (the baseline sits a few points above it).
		expect(origin.y).toBeGreaterThan(MARGIN - 2);
		expect(origin.y).toBeLessThan(MARGIN + 20);
		// The glyphs read horizontally: the drawn angle cancels the page rotation.
		expect(Math.round(getPageTextAngle(matrix))).toBe(rotation);
		expect(getPageText(output, 0)).toBe('Bl. 1');
	});
}

test('a mark that does not fit raises a TextOverlayError instead of shrinking forever', async () => {
	const document = await PDFDocument.create();
	const font = await document.embedFont(StandardFonts.Helvetica);
	const page = document.addPage([120, 160]);

	expect(() =>
		drawTextOverlay(page, {
			font,
			text: 'Ein sehr langer Stempeltext, der nicht auf die Seite passt',
			size: 18,
			color: rgb(0, 0, 0),
			position: 'bottom-center',
			margin: MARGIN,
			framed: true
		})
	).toThrow(TextOverlayError);
});

test('characters the standard font cannot encode are reported as such', async () => {
	const document = await PDFDocument.create();
	const font = await document.embedFont(StandardFonts.Helvetica);
	const page = document.addPage([PAGE_WIDTH, PAGE_HEIGHT]);

	let thrown: unknown;
	try {
		drawTextOverlay(page, {
			font,
			text: 'Beschluss \u{1F600}',
			size: 11,
			color: rgb(0, 0, 0),
			position: 'top-right',
			margin: MARGIN
		});
	} catch (error) {
		thrown = error;
	}

	expect(thrown).toBeInstanceOf(TextOverlayError);
	expect((thrown as Error).message).toContain('nicht dargestellt werden');
});

test('a rotated mark keeps its bounding box inside the page', async () => {
	const boxWidth = 200;
	const boxHeight = 40;

	for (const angle of [0, 45, 90, 135]) {
		const placement = getRotatedBoxPlacement(
			PAGE_WIDTH,
			PAGE_HEIGHT,
			boxWidth,
			boxHeight,
			'bottom-center',
			angle,
			TEXT_OVERLAY_MARGIN
		);

		expect(placement.x).toBeGreaterThanOrEqual(TEXT_OVERLAY_MARGIN - 0.001);
		expect(placement.y).toBeGreaterThanOrEqual(TEXT_OVERLAY_MARGIN - 0.001);
		expect(placement).not.toHaveProperty('cosine');
	}
});